The default TCP port number to use when connecting to
the database server if no other port is specified. If
no default is specified, the port will be obtained
from the MYSQL_TCP_PORT environment
variable, the mysql-tcp entry in
/etc/services or the compile-time
MYSQL_PORT constant, in that order. Win32
will only use the MYSQL_PORT constant.

Users cannot set MYSQL_OPT_READ_TIMEOUT through an API
call or runtime configuration setting. Note that if it were possible there
would be differences between how libmysqlclient and
streams would interpret the value of MYSQL_OPT_READ_TIMEOUT.